Johnston County Research Articles

Foot Disorders Associated With Overpronated and Oversupinated Foot Function: The Johnston County Osteoarthritis Project

Foot Disorders Associated With Overpronated and Oversupinated Foot Function: The Johnston County Osteoarthritis Project

Incident symptomatic hip osteoarthritis is associated with differences in hip shape by active shape modeling: The Johnston County Osteoarthritis Project

Incident symptomatic hip osteoarthritis is associated with differences in hip shape by active shape modeling: The Johnston County Osteoarthritis Project

Meeting Physical Activity Guidelines and the Risk of Incident Knee Osteoarthritis: A Population‐Based Prospective Cohort Study

Knee osteoarthritis (OA) is a leading cause of disability and joint pain. Although other risk factors of knee OA have been identified, how physical activity affects incident knee OA remains unclear. Using data from the first (1999-2004) and second (2005-2010) followup periods of the Johnston County Osteoarthritis Project study, we tested the association between meeting physical activity guidelines and incident knee outcomes among 1,522 adults ages ≥45 years. The median followup time was 6.5 years (range 4.0-10.2 years). Physical activity at baseline (moderate-equivalent physical activity minutes/week) was calculated using the Minnesota Leisure Time Physical Activity questionnaire. Incident knee radiographic OA (ROA) was defined as the development of Kellgren/Lawrence grade ≥2 in a knee at followup. Incident knee symptomatic ROA (sROA) was defined as the development of ROA and symptoms in at least 1 knee at followup. Weibull regression modeling was used to estimate hazard ratios (HRs) and 95% confidence intervals (95% CIs) for interval-censored data. In multivariable models, meeting the 2008 Department of Health and Human Services (HHS) physical activity guidelines (≥150 minutes/week) was not significantly associated with ROA (HR 1.20 [95% CI 0.92-1.56]) or sROA (HR 1.24 [95% CI 0.87-1.76]). Adults in the highest level (≥300 minutes/week) of physical activity had a higher risk of knee ROA and sROA compared with inactive (0 to <10 minutes/week) participants; however, these associations were not statistically significant (HR 1.62 [95% CI 0.97-2.68] and HR 1.42 [95% CI 0.76-2.65], respectively). Meeting the HHS physical activity guidelines was not associated with incident knee ROA or sROA in a cohort of middle-aged and older adults.

Association of Incident Symptomatic Hip Osteoarthritis With Differences in Hip Shape by Active Shape Modeling: The Johnston County Osteoarthritis Project

To investigate hip shape by active shape modeling (ASM) as a potential predictor of incident radiographic hip osteoarthritis (RHOA) and symptomatic hip osteoarthritis (SRHOA). All hips developing RHOA from baseline (Kellgren/Lawrence [K/L] grade 0/1) to mean 6-year followup (K/L grade ≥2, 190 hips) and 1:1 control hips (K/L grade 0/1 at both times, 192 hips) were included. Proximal femur shape was defined on baseline anteroposterior pelvis radiographs and submitted to ASM, producing a mean shape and continuous variables representing independent modes of shape variation. Mode scores (n = 14, explaining 95% of shape variance) were simultaneously included in logistic regression models with incident RHOA and SRHOA as dependent variables, adjusted for intraperson correlations, sex, race, body mass index (BMI), baseline K/L grade, and/or symptoms. We evaluated 382 hips from 342 individuals: 61% women and 83% white, with mean age 62 years and mean BMI 29 kg/m(2) . Several modes differed by sex and race, but no modes were associated with incident RHOA overall. Among men only, modes 1 and 2 were significantly associated (for a 1-SD decrease in mode 1 score: odds ratio [OR] 1.7 [95% confidence interval (95% CI) 1.1-2.5] and for a 1-SD increase in mode 2 score: OR 1.5 [95% CI 1.0-2.2]) with incident RHOA. A 1-SD decrease in mode 2 or 3 score increased the odds of SRHOA by 50%. This study confirms other reports that variations in proximal femur shape have a modest association with incident hip OA. The observation of proximal femur shape associations with hip symptoms requires further investigation.

Association analysis of BMD-associated SNPs with knee osteoarthritis.

Osteoarthritis (OA) risk is widely recognized to be heritable but few loci have been identified. Observational studies have identified higher systemic bone mineral density (BMD) to be associated with an increased risk of radiographic knee osteoarthritis. With this in mind, we sought to evaluate whether well-established genetic loci for variance in BMD are associated with risk for radiographic OA in the Osteoarthritis Initiative (OAI) and the Johnston County Osteoarthritis (JoCo) Project. Cases had at least one knee with definite radiographic OA, defined as the presence of definite osteophytes with or without joint space narrowing (Kellgren-Lawrence [KL] grade ≥ 2) and controls were absent for definite radiographic OA in both knees (KL grade ≤ 1 bilaterally). There were 2014 and 658 Caucasian cases, respectively, in the OAI and JoCo Studies, and 953 and 823 controls. Single nucleotide polymorphisms (SNPs) were identified for association analysis from the literature. Genotyping was carried out on Illumina 2.5M and 1M arrays in Genetic Components of Knee OA (GeCKO) and JoCo, respectively and imputation was done. Association analyses were carried out separately in each cohort with adjustments for age, body mass index (BMI), and sex, and then parameter estimates were combined across the two cohorts by meta-analysis. We identified four SNPs significantly associated with prevalent radiographic knee OA. The strongest signal (p = 0.0009; OR = 1.22; 95% CI, 1.08-1.37) maps to 12q3, which contains a gene coding for SP7. Additional loci map to 7p14.1 (TXNDC3), 11q13.2 (LRP5), and 11p14.1 (LIN7C). For all four loci the allele associated with higher BMD was associated with higher odds of OA. A BMD risk allele score was not significantly associated with OA risk. This meta-analysis demonstrates that several genomewide association studies (GWAS)-identified BMD SNPs are nominally associated with prevalent radiographic knee OA and further supports the hypothesis that BMD, or its determinants, may be a risk factor contributing to OA development. © 2014 American Society for Bone and Mineral Research.

English

Introduction The prevalence of knee osteoarthritis is much higher in Caucasians than in Asians or in black people. Few population-based studies regarding the incidence of knee osteoarthritis were found, with the incidence of knee osteoarthritis being higher in Japanese than in Caucasians. However, strict comparisons among these studies are limited, because the definition of the incidence of knee osteoarthritis is not the same for each study. A few risk factors for knee osteoarthrit is were established, such as female gender and obesity. Several crosssectional studies have found that the presence of a previous knee injuryis significantly associated with the incidence of knee osteoarthritis, but longitudinal studies did not find this significant correlation. However, the same longitudinal studies found significant associations between previous knee injuries and incident knee pain. One of the limitations in previous studies is the definition of knee osteoarthritis. The most popular grading system for knee osteoarthritis is Kellgren–Lawrence classification. However, joint space narrowing and osteophytosis cannot be separately assessed in this grading system. Recent studies have suggested distinct causes for both joint space narrowing and osteophytosis. These studies have also found an independent association between joint space narrowing and osteophytosis with the quality of life of the person. This is a review of population-based studies for knee osteoarthritis. Conclusion To further assess new risk factors or markers, joint space narrowing and osteophytosis should be assessed separately using a fully automatic system that measures joint space width and osteophyte area. Introduction Knee osteoarthritis (OA) is a major public health issue and causes chronic pain and disability among elderly in most of the developed countries. It is characterised by several pathological features, including joint space narrowing and osteophytosis. Despite the urgent need of strategies for the prevention and treatment of this condition, demographics on the overall disease prevalence and the affected subgroups are not adequately characterised yet. The reported prevalence of radiographic knee OA differs considerably among previous population-based epidemiologic studies.In addition, apart from age, sex, obesity and occupational activities, there are only a few other established risk factors for knee OA. We aimed to review the literature on population-based studies investigating knee OA. Prevalence of knee osteoarthritis Twelve previously published studies on the prevalence of knee OA were identified after performing a search in the English literature1–12 (Table 1). Epidemiologic studies on elderly Caucasians in the United States and Europe have shown that the prevalence of knee OA with Kellgren– Lawrence(KL) grade 2 or higher was 30–40%; where as studies in Asia have found a prevalence of 60% or higher. Thus, the prevalence of knee OA is higher in Asian populations than in Caucasian populations. Based on these studies, Caucasians show a lower prevalence of radiographic OA than that found in other races. Furthermore, the Johnston County study and the National Health and Nutrition Examination Survey (NHANES) studies reported that African-Americans have a higher prevalence of radiographic knee OA than did Caucasians. However, in the NHANES studies, the prevalence rates of knee OA were lower than those in other studies;this discrepancy was explained by differences in radiographic acquisition. In these studies, knee radiographs were obtained in a non-weight-bearing position, as opposed to other studies, where in knee radiographs were obtained in a weight-bearing position. The Chingford study presented lower prevalence of knee OA because subjects were much younger than those who participated in other studies. In terms of KL grading, KL grade 2 indicates the presence of osteophyte formation; and grade 3 indicates joint space narrowing in addition to osteophyte formation; KL ≥ 2 is generally thought to be the standard for the diagnostic criterion of knee OA13. However, accumulating evidence has shown that osteophytosis and joint space narrowing have distinct aetiologic mechanisms, and their progression is neither constant nor proportional14. Hence, to assess these two pathological features separately, the * Corresponding author Email: murakis-ort@h.u-tokyo.ac.jp 1 Department of Clinical Motor System Medicine, 22nd Century Medical and Research Center, Faculty of Medicine, University of Tokyo,7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8655, Japan 2 Department of Orthopaedic Surgery, Faculty of Medicine, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8655, Japan 3 Department of Joint Disease Research, 22nd Century Medical & Research Center, Faculty of Medicine, University of Tokyo,7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8655, Japan

Independent associations of socioeconomic factors with disability and pain in adults with knee osteoarthritis.

BackgroundThe purpose of this study is to explore the relationship between function, pain and stiffness outcomes with individual and community socioeconomic status (SES) measures among individuals with radiographic knee osteoarthritis (rOA).MethodsCross-sectional data from the Johnston County Osteoarthritis Project were analyzed for adults age 45 and older with knee rOA (n = 782) and a subset with both radiographic and symptomatic knee OA (n = 471). Function, pain and stiffness were measured using the Western Ontario and McMasters Universities Index of Osteoarthritis (WOMAC). Individual SES measures included educational attainment (<12 years, ≥12 years) and occupation type (managerial, non-managerial), while community SES was measured using Census block group poverty rate (<12%, 12-25%, ≥25%). SES measures were individually and simultaneously examined in linear regression models adjusting for age, gender, race, body mass index (BMI), occupational physical activity score (PAS), comorbidity count, and presence of hip symptoms.ResultsIn analyses among all individuals with rOA, models which included individual SES measures were observed to show that occupation was significantly associated with WOMAC Function (β =2.91, 95% Confidence Interval (CI) = 0.68-5.14), WOMAC Pain (β =0.93, 95% CI = 0.26-1.59) and WOMAC Total scores (β =4.05, 95% CI = 1.04-7.05), and education was significantly associated with WOMAC Function (β =3.57, 95% CI = 1.25-5.90) and WOMAC Total (β =4.56, 95% CI = 1.41-7.70) scores. In multivariable models including all SES measures simultaneously, most associations were attenuated. However, statistically significant results for education remained between WOMAC Function (β =2.83, 95% CI = 0.38-5.28) and WOMAC Total (β =3.48, 95% CI = 0.18-6.78), as well as for the association between occupation and WOMAC Pain (β =0.78, 95% CI = 0.08-1.48). In rOA subgroup analyses restricted to those with symptoms, we observed a significant increase in WOMAC Pain (β =1.36, 95% CI = 0.07-2.66) among individuals living in a block group with poverty rates greater than 25%, an association that remained when all SES measures were considered simultaneously (β =1.35, 95% CI = 0.06-2.64).ConclusionsLower individual and community SES are both associated with worse function and pain among adults with knee rOA.

First Report of Meloidogyne enterolobii on Cotton and Soybean in North Carolina, United States.

Stunted cotton plants (Gossypium hirsutum L. cvs. PHY 375 WR and PHY 565 WR) from two separate fields near Goldsboro in Wayne County, North Carolina were collected by the NCDA&CS Agronomic Division nematode lab for nematode assay and identification in December 2011. The galls on cotton plants were very large in comparison with those commonly associated with Meloidogyne incognita Kofoid and White (Chitwood) infected cotton. In August 2012, the lab also received heavily galled roots of soybean (Glycine max (L.) Merr. cv. 7732) from Wayne and Johnston counties. Population densities of the 2nd-stage juveniles ranged from 150 to 3,800 per 500 cc soil. Female perineal patterns were similar to M. incognita, but PCR and DNA sequencing matched that of M. enterolobii Yang and Eisenback (4). DNA sequences of ribosomal DNA small subunit, internal transcribed spacer, large subunit domain 2 and 3, intergeneric spacer, RNA polymerase II large subunit, and histone gene H3, were found to be 100% homologous when comparing populations of M. enterolobii from North Carolina and China. Species identification was also confirmed using PCR by a species-specific SCAR primer set MK7-F/MK7-R (2). M. enterolobii Yang & Eisenback was described in 1983 from a population causing severe damage to pacara earpod tree (Enterolobium contortisiliquum (Vell.) Morong) in China (4). In 2004, M. mayaguensis Rammah & Hirschmann, a species described from Puerto Rico, was synonymized with M. enterolobii based on esterase phenotype and mitochondrial DNA sequence (3). M. enterolobii is considered to be a highly pathogenic species and has been reported from vegetables, ornamental plants, guava, and weeds in China, Africa, Central and South America, the Caribbean, and Florida in the United States (1,3,4). Of particular concern is its ability to develop on crop genotypes carrying root-knot-nematode resistance genes (Mi-1, Mh, Mir1, N, Tabasco, and Rk) in tobacco, tomato, soybean, potato, cowpea, sweet potato, and cotton. Consequently, this species was added to the European and Mediterranean Plant Protection Organization A2 Alert list in 2010. Two populations of M. enterolobii one from soybean and one from cotton were reared on tomato (Solanum lycopersicum L. var. lycopersicum) in a greenhouse setting. Eggs were extracted using NaOCl and inoculated, at a rate of 7,000 per 15-cm-diameter clay pot, into a sandy soil mixture (1:1 washed river sand and loamy sand). Tomato, peanut (Arachis hypogaea L.), cotton, watermelon (Citrullus lanatus (Thunb.) Matsum. & Nakai), pepper (Capsicum annuum L.), and root-knot-susceptible and -resistant tobacco (Nicotiana tabacum L. cvs. K326 and NC 70, respectively) were transplanted immediately into the infested soil with four replications. Root galls on the host differentials were evaluated after 90 days. Reproduction occurred on all hosts except for peanut, which is consistent with reports for M. enterolobii and M. incognita race 4 (4). Adult females from pepper plants used in the host differential test were sequenced on partial 18S and ITS1 region and confirmed to be M. enterlobii. To our knowledge, this is the first report of a natural infection of North Carolina field crops with M. enterolobii.

Time to Think About Osteoarthritis Management in the Context of Other Chronic Conditions

Joanne M Jordan, MD MPH, received her undergraduate education at Cornell University (NY, USA); her medical education at The Johns Hopkins Medical Institutions (MD, USA); and her masters in public health at the University of North Carolina School of Public Health (NC, USA). She received training in internal medicine and subspecialty training in rheumatology and immunology at Duke University Medical Center (NC, USA). She joined the faculty of the Division of Rheumatology, Allergy and Immunology at the University of North Carolina in 1987. She currently is the Chief of the Division of Rheumatology, Allergy and Immunology and the Director of the Thurston Arthritis Research Center at the University of North Carolina. Her research interests are in the epidemiology and genetics of osteoarthritis and disability. She is the principal investigator of the Johnston County Osteoarthritis Project, a large, &gt;20-year, community-based prospective study of individuals aged 45 years and older. The study is the first of its type to include both African–Americans and Caucasians, and is unique in its inclusion of radiographic, serologic, genetic, and physical and functional phenotypic examinations of its participants for multiple chronic diseases. Dr Jordan currently serves as Chair of the US Bone and Joint Initiative’s Chronic Osteoarthritis Management Initiative, whose goal is to change the medical paradigm regarding osteoarthritis by incorporating joint health assessment and management into routine medical care. She is the Deputy Editor for Clinical Science of the journal Osteoarthritis and Cartilage and is a member of the Board of Directors of the Osteoarthritis Research Society International. She is the recipient of the Osteoarthritis Research Society International’s Clinical Research Award in 2007, the 2009 American College of Rheumatology Award of Distinction in Investigative Mentoring and the 2011 Rural Sociological Society’s Distinguished Service to Rural Life Award.

Associations of Educational Attainment, Occupation, and Community Poverty With Hip Osteoarthritis

To examine cross-sectional baseline data from the Johnston County Osteoarthritis Project for the association between individual and community socioeconomic status (SES) measures with hip osteoarthritis (OA) outcomes. We analyzed data on 3,087 individuals (68% white and 32% African American). Educational attainment and occupation were used as individual measures of SES. Census block group household poverty rate was used as a measure of community SES. Hip OA outcomes included radiographic OA and symptomatic OA in one or both hip joints. Multivariable logistic regression models were used to estimate odds ratios (ORs) and 95% confidence intervals (95% CIs) for the association of each hip OA outcome with each SES variable separately, and then with all SES measures simultaneously. Associations between hip OA outcomes and SES variables were evaluated for effect modification by race and sex. Living in a community of high household poverty rate showed independent associations with hip radiographic OA in one or both hips (OR 1.50, 95% CI 1.18-1.92) and bilateral (both hips) radiographic OA (OR 1.87, 95% CI 1.32-2.66). Similar independent associations were found between low educational attainment among those with symptomatic OA in one or both hips (OR 1.44, 95% CI 1.09-1.91) or bilateral symptomatic OA (OR 1.91, 95% CI 1.08-3.39), after adjusting for all SES measures simultaneously. No significant associations were observed between occupation and hip OA outcomes, nor did race or sex modify the associations. Our data provide evidence that hip OA outcomes are associated with both education and community SES measures, associations that remained after adjustment for covariates and all SES measures.

Occurrence of Radiographic Osteoarthritis of the Knee and Hip Among African Americans and Whites: A Population‐Based Prospective Cohort Study

To compare the incidence and progression of radiographic osteoarthritis (OA) in the knee and hip among African Americans and whites. Using the joint as the unit of analysis, we analyzed data from the Johnston County Osteoarthritis Project, a population-based prospective cohort study in rural North Carolina. Baseline and followup assessments were 3-13 years apart. Assessments included standard knee and hip radiographs read for Kellgren/Lawrence (K/L) radiographic grade. Weighted analyses controlled for age, sex, body mass index, level of education, and baseline K/L grade; bootstrap methods adjusted for lack of independence between left and right joints. Time-to-event analysis was used to analyze the data. For radiographic knee OA, being African American had no association with incidence (adjusted hazard ratio [HRadj ] 0.80, 95% confidence interval [95% CI] 0.53-1.22), but had a positive association with progression (HRadj 1.67, 95% CI 1.05-2.67). For radiographic hip OA, African Americans had a significantly lower incidence (HRadj 0.44, 95% CI 0.27-0.71), whereas the association with progression was positive but nonsignificant (HRadj 1.46, 95% CI 0.53-4.01). In sensitivity analyses, the association with hip OA incidence was robust to a wide range of assumptions. African Americans are protected against incident hip OA, but may be more susceptible to progressive knee OA.

Composite measures of multi-joint symptoms, but not of radiographic osteoarthritis, are associated with functional outcomes: the Johnston County Osteoarthritis Project

Purpose: To determine associations between multiple joint symptoms and radiographic osteoarthritis (rOA) and functional outcomes. Method: Complete cross-sectional data for multi-joint symptoms and radiographs, Health Assessment Questionnaire (HAQ) scores, and gait speed were available for 1307 Johnston County Osteoarthritis Project participants (34% men, 32% African American, mean age 66 years). Factor analysis of symptom scores and radiographic grades for the lumbosacral spine, bilateral hands, knees, and hips provided composite scores. Regression models were used to determine associations between composite scores, HAQ, and gait speed, adjusting for age, body mass index, gender, and race. Results: Five rOA factors were identified: (1) IP/CMC factor (carpometacarpal [CMC] and all interphalangeal [IP] joints); (2) MCP factor (metacarpophalangeal joints 2–5); (3) Knee factor (tibiofemoral and patellofemoral joints); (4) Spine factor (L1/2 to L5/S1); and (5) Symptom factor. After adjustment, only the Symptom composite was significantly associated with HAQ and gait speed; a 1-standard deviation increase in Symptom score was associated with 9 times higher odds of having poorer function on the HAQ (odds ratio 9.32, 95% confidence interval [CI] 6.80, 12.77), and a clinically significant decline in gait speed (0.06 m/s, 95% CI −0.07, −0.05). Conclusions: A novel Symptom composite score was associated with poorer functional outcomes.Implications for RehabilitationOsteoarthritis (OA) commonly affects multiple joints and is the most common form of arthritis.Symptomatic assessments, which can be easily executed by rehabilitation practitioners, are more closely related to self-reported and performance-based functional status than are less accessible and more costly radiographs.Symptomatic assessments are likely to be more informative for understanding, treating, and potentially preventing functional limitations than radiographic assessments.

LEG muscle mass and foot pain, structure and function: the Johnston County Osteoarthritis Project

LEG muscle mass and foot pain, structure and function: the Johnston County Osteoarthritis Project

Association between pain-pressure threshold, low back symptoms and lumbar spine individual radiographic features: the Johnston County Osteoarthritis Project

Association between pain-pressure threshold, low back symptoms and lumbar spine individual radiographic features: the Johnston County Osteoarthritis Project

Race interactions and foot function in older adults: the Johnston County Osteoarthritis Project

285 RACE INTERACTIONS AND FOOT FUNCTION IN OLDER ADULTS: THE JOHNSTON COUNTY OSTEOARTHRITIS PROJECT M.T. Hannan y, A.B. Dufour z, Y.M. Golightly x, V.A. Casey z, T.J. Hagedorn z, J.L. Riskowski y, H.J. Hillstrom k, J.M. Jordan x. yHebrew SeniorLife & Harvard Med. Sch., Roslindale, MA, USA; zHebrew SeniorLife, Roslindale, MA, USA; xUniv. of North Carolina, Chapel Hill, NC, USA; kHosp. for Special Surgery, NY, USA

Brief report: differences in multijoint symptomatic osteoarthritis phenotypes by race and sex: the Johnston County Osteoarthritis Project.

To determine differences in the phenotypes (patterns) of multiple-joint symptomatic osteoarthritis (OA) involvement by race and sex. A cross-sectional analysis of symptomatic OA phenotypes was performed in a community-based cohort, comprising subjects for whom data were collected from 4 sites of symptomatic OA involvement (the hands, knees, hips, and lumbosacral [LS] spine) at a single visit (2003-2010). Mutually exclusive phenotypes describing all combinations of these 4 sites were compared by race and by sex, using Fisher's exact tests. For those phenotypes occurring in >40 subjects, logistic regression was performed, with adjustments for race, sex, age, and body mass index (BMI), and interactions of race and sex were assessed. The sample included 1,650 participants, of whom 36% were men and 32% were African American. The mean age of the subjects was 66 years, and the mean BMI was 31 kg/m(2). Overall, in this sample, 13% of subjects had symptomatic hand OA, 25% had symptomatic knee OA, 11% had symptomatic hip OA, and 28% had symptomatic LS spine OA. African Americans, as compared with Caucasians, were less likely to have involvement of symptomatic OA in the hand only, or in some combination of the hand and other sites, but were more likely to have involvement of the knee only. Men, as compared to women, were less likely to have involvement of the hand only, but were more likely to have involvement of the LS spine only. There are differences in the phenotypes of multiple-joint symptomatic OA involvement by race and by sex that may influence the definitions of multiple-joint, or generalized, OA.

Differences in Multi-joint Symptomatic Osteoarthritis Phenotypes by Race and Gender: The Johnston County Osteoarthritis Project

Differences in Multi-joint Symptomatic Osteoarthritis Phenotypes by Race and Gender: The Johnston County Osteoarthritis Project

Racial differences in foot disorders and foot type

To describe racial differences in the frequency of structural foot disorders and pes planus and pes cavus foot types in a large cohort of African American and white men and women ages ≥50 years. Of 1,695 Johnston County Osteoarthritis Project participants evaluated for foot disorders/types in 2006-2010, 4 with lower extremity amputation were excluded, leaving 1,691 available for analyses (mean age 69 years, mean body mass index [BMI] 31.5 kg/m(2) , 68% women, 31% African American). The most common foot disorders/types were identified using a validated foot examination. Each foot disorder/type was compared by race using logistic regression, controlling for age, BMI, and sex. Effect modification between race (African American versus white) and age, BMI (categorized as ≥30 kg/m(2) [obese] or <30 kg/m(2) [nonobese]), sex, and education was examined. Hallux valgus (64%), hammer toes (35%), overlapping toes (34%), and pes planus (23%) were common. Compared to whites, African Americans were almost 3 times more likely to have pes planus and were nearly 5 times less likely to have Tailor's bunions or pes cavus. Among the nonobese, African Americans were more likely than whites to have hallux valgus (adjusted odds ratio [OR(adj) ] 2.01, 95% confidence interval [95% CI] 1.39-2.92), hammer toes (OR(adj) 2.64, 95% CI 1.88-3.70), and overlapping toes (OR(adj) 1.53, 95% CI 1.09-2.13). Foot disorders are common among adults ages ≥50 years and differ by race. Future research is needed to determine the etiology of foot problems, especially those with racial differences, in order to inform prevention approaches.

Lumbar spine radiographic features and demographic, clinical, and radiographic knee, hip, and hand osteoarthritis

To determine the prevalence of lumbar spine individual radiographic features (IRFs) of disc space narrowing (DSN), osteophytes (OST), and facet joint osteoarthritis (FOA); to describe the frequencies of demographic, clinical, and radiographic knee, hip, and hand osteoarthritis (OA) across lumbar spine IRFs; and to determine factors associated with lumbar spine IRFs. We conducted a cross-sectional study of 840 participants enrolled in the Johnston County Osteoarthritis Project (2003-2004). Sample-based prevalence estimates were generated for each lumbar spine IRF. The associations between lumbar spine IRFs and demographic, clinical, and peripheral joint OA were determined with logistic regression models. Sample-based prevalence estimates were similar for DSN (57.6%) and FOA (57.9%) but higher for OST (88.1%), with significant differences across race and sex. Hand and knee OA frequencies increased across IRFs, whereas the effect was absent for hip OA. African Americans had lower odds of FOA (adjusted odds ratio [OR(adj) ] 0.45 [95% confidence interval (95% CI) 0.32-0.62]), while there was no racial association with DSN and OST. Low back symptoms were associated with DSN (OR(adj) 1.37 [95% CI 1.04-1.80]) but not OST or FOA. Knee OA was associated with OST (OR(adj) 1.62 [95% CI 1.16-2.27]) and FOA (OR(adj) 1.69 [95% CI 1.15-2.49]) but not DSN. Hand OA was associated with FOA (OR(adj) 1.67 [95% CI 1.20-2.28]) but not with DSN or OST. No associations were found with hip OA. These findings underscore the importance of analyzing lumbar spine IRFs separately as the associations with demographic, clinical, and radiographic knee, hip, and hand OA differ widely.

Association of dietary magnesium intake with radiographic knee osteoarthritis: Results from a population‐based study

To examine the cross-sectional association between dietary magnesium intake and radiographic knee osteoarthritis (OA) among African American and white men and women. The presence of radiographic knee OA was examined among participants from the Johnston County Osteoarthritis Project and was defined as a Kellgren/Lawrence grade of at least 2 in at least 1 knee. The Block Food Frequency Questionnaire was used to assess magnesium intake. Effect modifiers were explored by testing interactions of magnesium intake and selected factors based on previous studies. The multivariable logistic regression model with standard energy adjustment method was used to estimate the relationship between magnesium intake and radiographic knee OA. The prevalence of knee OA was 36.27% among the 2,112 participants. The relationship between magnesium intake and radiographic knee OA was found to be modified by race (P for interaction = 0.03). An inverse threshold association was observed among whites. Compared to participants in the lowest quintile, the relative odds of radiographic knee OA were cut by one-half for participants in the second quintile of magnesium intake (odds ratio 0.52, 95% confidence interval 0.34-0.79); further magnesium intake did not provide further benefits (P for trend = 0.51). A statistically significant association was not observed among African Americans. A modest inverse threshold association was found between dietary magnesium intake and knee OA in whites, but not in African Americans. Further studies are needed to confirm these results and to elucidate the possible mechanisms of action for the racial modification.